The present invention relates to an automatic brake and steering system for a vehicle. More particularly, the present invention relates to such a system having a sensor unit for sensing vehicle state variables and vehicle characteristic variables as well as for sensing ambient conditions, having a control unit in which actuation signals can be generated as a function of the vehicle state variables and the ambient conditions, it being possible to feed actuation signals to actuation devices in the vehicle in order to set the vehicle brake and the vehicle steering system, the distance between the current position of the vehicle and the obstacle as well as the expected braking distance in order to stop the vehicle being determined when there is an obstacle in the path of the vehicle, and an avoidance path for driving around the obstacle being automatically driven along in accordance with a stored avoidance strategy.
DE 40 39 005 A1 discloses a control system for a vehicle which comprises a sensor arrangement, a central control unit and a multiplicity of actuator devices for various assemblies of a vehicle which influence the state of the vehicle. The sensor arrangement registers activities carried out by the driver, in particular a braking and a steering activity of the driver, and vehicle state variables, for example the speed of the vehicle and the wheel speeds are determined. The determined signals are processed, in accordance with a stored calculation rule, in the control unit in which actuation signals are generated which are fed to the actuator devices of the vehicle assemblies in order to manipulate the state of the vehicle. The assemblies to be influenced comprise, inter alia, the vehicle gearbox, a steering control device and a brake device.
This known control system has the disadvantage that only activities of the driver and the vehicle state can be sensed but not processes and states which take place or exist outside the vehicle. It is therefore not possible to sense possible obstacles on the carriageway and to take measures to avoid collisions. The control system described in DE 40 39 005 A1 cannot be used to implement automatic, autonomous driving.
WO 90/02985 A1 discloses a method and a device for automatically avoiding collisions for vehicles. The device and method include predictive sensing of an obstacle, the collision-avoiding avoidance maneuver being carried out when an obstacle is detected. When there is an object, an avoidance path is calculated in accordance with an avoidance strategy stored in the control unit. The actuator device for the steering is acted on in such a way that the vehicle follows the avoidance path and drives around the obstacle.
Although the brake and steering system described in WO 90/02985 A1 enables collisions with obstacles to be avoided in a predictive way by carrying out braking maneuvers and avoidance maneuvers, it is disadvantageous that the avoidance strategy does not contain any alternatives if further unexpected obstacles arise during the avoidance maneuver.